win32: Catch mouse events in window rather than display
EGL will most probably never supply an abstraction for inputs events. To alleviate the problem, mouse clicks and pointer movements should be captured by the vout window, as opposed to the vout display currently.
That requires adding mouse event callbacks to vout window, which will need to be implemented by XCB and Qt4 window plugins. Then it also requires a new vout display control request a change to video output core to translate mouse coordinates from window to video coordinates (the vout window has no notion of where the video is nor how it is scaled).
On the plus side, this removes some copy-cat code from all X11 plugins (XVideo, GLX, X11 and VDPAU): they no longer need to care about the mouse handling at all. See also #5514 (closed) and #7936 (closed).